Excavating tooth assembly and method for assembling and using the same

ABSTRACT

An excavating tooth assembly comprising a tooth holder and a tooth which are attachable together. The tooth includes a pair of prongs which are inserted into a pair of receptacles in the tooth holder and which embrace a web within the tooth holder. A pair of resilient members are attached either to the prongs or to the web and are compressed between the prongs and the web to aid in frictionally securing the tooth to the tooth holder.

BACKGROUND OF THE INVENTION

The present invention relates to an excavating tooth assembly and amethod for assembling and using an excavating tooth assembly.

Various devices and methods have been used to attach excavating teeth toexcavating equipment. In most existing devices, a tooth holder isattached to an excavating instrument such as an auger, and an excavatingtooth is detachably combined with to the tooth holder. The detachabilityof the excavating tooth from the excavating equipment allows the toothto be replaced or repaired when it is worn out or broken. In one type oftooth assembly, the tooth holder includes an elongated web member. Thetooth includes two spaced apart prongs which embrace the opposite sidesof the web. A resilient member is inserted between the prongs and theweb and is frictionally compressed therebetween to aid in holding thetooth to the tooth holder.

Various types of resilient members have been used to secure excavatingteeth to their tooth holders. In most prior art devices, the resilientmember is a U-shape that surrounds both sides of the web and the endnose of the web. Examples of these types of devices are shown in U.S.Pat. Nos. 5,184,412; 3,323,236; and 2,968,880.

Examples of U-shaped members used in the prior art are shown in FIGS. 5and 6. With reference to the device shown in FIG. 5, the numeral 66designates a tooth and the numeral 72 designates a tooth holder. Thetooth 66 includes a pair of spaced apart prongs 68, 70. The tooth holder72 includes a web 74 which is elongated and which includes a nose 80 atits end. A U-shaped resilient member 76 is shown between the prongs 68,70 and the web 74. This U-shaped member 76 is not attached to the tooth66, but is instead placed between the prongs 68, 70 and the web 74during insertion of the web 74 between the prongs 68, 70. Onedisadvantage of the resilient member 76 in this prior art device is thatit is not long enough to extend the entire length of the web 74 or theprongs 68, 70. Consequently, the tooth 66 becomes misaligned with thetooth holder 72 as can be seen at the contact point 82 and at the spacedapart point 84. This misalignment causes uneven wear on the tooth 66,and reduces the useful life of the tooth 66 during the cutting process.

FIG. 6 shows another example of a prior art U-shaped resilient membersimilar to the device shown in FIG. 5. However, the device shown in FIG.6 comprises resilient member 78 that is longer than the prongs 68, 70 sothat resilient member 78 has ends 86, 88 protruding outwardly from theslot between the two prongs 68, 70. One problem with the device shown inFIG. 6 is that it prevents the nose 80 from fitting tightly into theinterior end of the slot between prongs 68, 70. This reduces the area ofcontact between the resilient member 78 and the side walls of the web 74thereby reducing the resilient member's 78 ability to secure theexcavating tooth 66 to the tooth holder 72. Another problem with thisdevice is that the tooth 66 and tooth holder 72 are allowed to compressand recoil against the resilient member 78 due to the resilient member78 being between the tooth 66 and tooth holder 72 which reduces the lifeof the tooth 66.

Therefore, an object of the present invention is the provision of anexcavating tooth assembly which permits the nose of the web to engagethe inner end of the slot between the two prongs of the tooth.

A further object of the present invention is the provision of anexcavating tooth assembly which maximizes the area of contact betweenthe resilient members and the walls of the web.

A further object of the present invention is the provision of anexcavating tooth assembly which maximizes the area of contact betweenthe tooth and the resilient members.

A further object of the present invention is the provision of anexcavating tooth assembly which minimizes the wear to the tooth duringthe cutting operation.

A further object of the present invention is the provision of animproved excavating tooth assembly and method which is simple to use,economic to manufacturer, and efficient to operate.

SUMMARY OF THE INVENTION

The foregoing objects may be achieved with an excavating tooth assemblycomprising a tooth holder having upper and lower members and a webextending between the upper and lower members. The web is elongated andincludes a nose end and an inner end. It also has elongated first andsecond opposite side walls extending along the length thereof betweenthe nose end and the inner end. A tooth includes a cutting end and anattachment end. The attachment end has first and second spaced apartprongs adapted to embrace the first and second opposite side walls ofthe web, respectively. In one embodiment, a first resilient member isattached to the first prong and a second resilient member is attached tothe second prong. In use, the first resilient member is compressedbetween the first prong and the first side wall of the web and thesecond resilient member is compressed between the second prong and thesecond side wall of the web for frictionally securing the tooth to thetooth holder.

According to one feature of the invention the first and second spacedapart prongs define an elongated slot having a closed inner end and anopen outer end. The first and second resilient members each have anouter end adjacent the outer end of the slot and an inner end adjacentthe inner end of the slot. The nose end of the web engages the inner endof the slot and the first and second resilient members engage the firstand second opposite side walls of the web along substantially the entirelength thereof between the nose and the inner end of the web.

The method of assembling and using the present invention comprisesattaching the first and second resilient members to either the first andsecond prongs or to the first and second side walls of the web. Theprongs are then moved into an attached position engaging the first andsecond opposite side walls of the web so that the first resilient memberis compressed between the first prong and the first side wall of the weband the second resilient member is compressed between the second prongand the second side wall of the web.

It should be understood that although the present invention hasparticular application to earth augers, trenching machines, and thelike, its may be used to secure teeth to other machinery includinggraters, dippers, backhoes, harrows, scarifiers, cable plows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the excavating tooth assembly of thepresent invention showing the tooth separated from the tooth holder;

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a sectional view similar to FIG. 2 showing the tooth attachedto the tooth holder;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a sectional view of a prior art excavating tooth assemblyhaving a U-shaped resilient member that is shorter than the prongs; and

FIG. 6 is a sectional view of a prior art excavating tooth assemblyhaving a U-shaped resilient member that is longer than the prongs.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings, the numeral 10 generally designates theexcavating tooth assembly of the present invention. Assembly 10 includesa tooth 12 and a tooth holder 14. The tooth holder 14 is combined with amachine such as an auger or backhoe. Tooth 12 includes a cutting end 16and an attachment end 18. Cutting end 16 has a tooth edge 20 and a pairof side reinforcing ribs 22. Tooth 12 also includes at the opposite enda first prong 24 and a second prong 26 which are spaced apart and whichform a U-shaped slot 28. Slot 28 includes an open end 30 and a closedend 32. In one embodiment the tooth 16 is comprised of steel, howeverany other suitable material may be used.

As seen best in FIGS. 1-4, attached to the prongs 24, 26 are a firstresilient member 34 and a second resilient member 36, respectively.Resilient members 34, 36 may be comprised of rubber or any othersuitable material which is capable of compressing and which is capableof exerting a friction against an elongated member on the tooth holder14. The elongated member is sometimes referred to in the industry as aweb 50. In one embodiment, the resilient members 34, 36 comprise atapered outer end 38 and a tapered inner end 40. The tapered outer end38 is tapered to help the tooth 12 combine with the tooth holder 14without damage to the resilient member 34, 36. Tapered inner end 40 istapered to help the resilient members 34, 36 fit properly against thecurved portion of the tooth's 12 closed inner end 32. It should be notedthat the two resilient members 34, 36 leave the closed end 32 of theslot 28 exposed so as to not cover the closed inner end 32 (FIG. 2).

The resilient member 34, 36 may be combined with the inner edges of theprongs 24, 26 by any suitable means, including adhesively, mechanically(such as screws or rivets), or by a process of vulcanization. Thepreferred method of combining the resilient members 34, 36 with theprongs 24, 26 is by a vulcanization process in which an adhesive isvulcanized to the metal prongs 24, 26. In this vulcanization process,adhesives are applied between the resilient material 34, 36 and theprongs 24, 26. The rubber of the resilient material 34, 36 is held toits respective prong 24, 26 by an adhesive that is exposed to atemperature of about 160° C. for about eight minutes. Then, a compressedset of the adhesive is applied at about 70° C. for about twenty-twohours. The resulting resilient material has a hardness of about 67(a),which is measured on the Durometer scale. It has a tinsel strength ofabout 17.32 Mega Pascals (Mpa).

In an alternate embodiment, the resilient members 34, 36 are attached tothe side walls 56, 58 of web 50 instead of attaching the resilientmembers 34, 36 to the inner surfaces of prongs 24, 26. This attachmentmay be by any of the same attachment means described in the previousparagraph including adhesively, mechanically (such as screws or rivets),or by a process of vulcanization.

As best seen in FIGS. 1 and 2, the tooth holder 14 includes a closedportion 42 at one end to which are joined an upper jaw member 44 and alower jaw member 46 which are spaced apart from one another. A notch 48is formed in the lower jaw member 46. The notch 48 is adapted to receivea drift punch, screw driver head, or any other suitable tool that can beused to pry the tooth 12 from the tooth holder 12. As best seen in FIG.2, an elongated web 50 extends from the closed portion 42 into the spacebetween the upper jaw member 44 and the lower jaw member 46. A closedside wall 51 extends along one side of the tooth holder 14 between theupper jaw member 44 and the lower jaw member 46. Web 50 includes aninner end 52 adjacent the closed portion 42 and a nose end 54. Nose end54 conforms to the closed inner end 32 of the slot 28 of tooth 16. Web50 includes first and second elongated concave side walls 56, 58. Theconcave side walls 56, 58 are adapted to receive a locking means such asa ribbed rubber lock to help secure the tooth 12 to the tooth holder 14.Spaces on the opposite side of web 50 form prong receiving slots 60, 62for receiving the prongs 24, 26 of the tooth 16.

As best seen in FIG. 1, the upper surfaces of prongs 24, 26 includeV-shaped notches 64 therein. These V-shaped notches 64 are configured toreceive inserts or pegs (not shown) as disclosed in U.S. Pat. No.2,968,880, the disclosure of which is incorporated herein by reference.

In order to attach the tooth 16 to the tooth holder 14, the prongs 24,26 are inserted into the receptacles 60, 62 respectively so that theprongs 24, 26 engage the opposite side walls of the web 50. Thedimensions of the slot 28 and the thickness of the web 50 are chosen sothat the resilient members 34, 36 are tightly compressed against theopposite side walls 56, 58 of the web 50. This compression causesfrictional engagement of the tooth 16 to the tooth holder 42.

Referring to FIG. 3, several features of the excavating tooth assembly10 are shown. First, the nose end 54 of the web 50 engages the inner end32 of slot 28. This metal to metal contact is not achieved in knownprior devices. The metal to metal contact increases the life of thetooth 12 because the tooth's 12 movement relative to the tooth holder 14is reduced relative to prior art devices (FIGS. 5 and 6) in which thetooth 66 and tooth holder 72 would compress and recoil due to theresilient member 76, 78 being between the tooth 66 and tooth holder 72.Second, the resilient members 34, 36, engage the side walls 56, 58 alongsubstantially the entire length thereof. This increases the surface areaof frictional engagement, and provides a tighter attachment. Third, theresilient members 34, 36 are evenly compressed on the opposite sides ofthe web 50 so as to insure that the tooth 20 is not misaligned, and thatit is securely held in place.

In the drawings and specification there has been set forth a preferredembodiment of the invention, and although specific terms are employed,these are used in an illustrative and descriptive sense only and not forpurposes of limitation. Changes in the form and the proportion of partsas well as in the substitution of equivalents are contemplated ascircumstances may suggest or render expedient without departing from thespirit or scope of the invention as further defined in the followingclaims.

1. A tooth assembly comprising: a tooth holder; a tooth adapted to becombined with the tooth holder; a first resilient member combined withthe tooth and adapted to frictionally secure the tooth to the toothholder; a second resilient member combined with the tooth and adapted tofrictionally secure the tooth to the tooth holder.
 2. The tooth assemblyof claim 1 wherein the tooth has an opening adapted to receive a portionof the tooth holder, said opening having an inner end and an outer end.3. The tooth assembly of claim 2 wherein the inner end of the opening isadapted to engage a portion of the tooth holder when the tooth and toothholder are combined.
 4. The tooth assembly of claim 2 wherein thetooth's opening further comprises a first wall substantially parallel toa second wall; wherein the first resilient member is combined withsubstantially the entire length of the tooth opening's first wall; andwherein the second resilient member is combined with substantially theentire length of the tooth opening's second walls.
 5. A tooth assemblycomprising: a tooth holder; a tooth adapted to be combined with thetooth holder; a first resilient member combined with the tooth holderand adapted to frictionally secure the tooth to the tooth holder; asecond resilient member combined with the tooth holder and adapted tofrictionally secure the tooth to the tooth holder.
 6. The tooth assemblyof claim 5 wherein the tooth has an opening adapted to receive a portionof the tooth holder, said opening having an inner end and an outer end.7. The tooth assembly of claim 6 wherein the inner end of the opening isadapted to engage a portion of the tooth holder when the tooth and toothholder are combined.
 8. The tooth assembly of claim 6 wherein the toothholder further comprises a web adapted to be received by the tooth'sopening, said web having a first wall substantially parallel to a secondwall; wherein the first resilient member is combined with substantiallythe entire length of the web's first wall; and wherein the secondresilient member is combined with substantially the entire length of theweb's second wall.
 9. A tooth assembly comprising: a tooth holder havingupper and lower members and a web extending between said upper and lowermembers; said web being elongated and having a nose end, an inner end,and an elongated first and second opposite side walls extending alongthe length thereof between said nose end and said inner end; a toothhaving a cutting end and an attachment end, said attachment end havingfirst and second spaced apart prongs adapted to engage said first andsecond opposite side walls of said web; a first resilient memberattached to one of said first prong and said first side wall of said weband a second resilient member attached to one of said second prong orsaid second side wall of said web; said first resilient member adaptedto be compressed between said first prong and said first side wall ofsaid web to frictionally secure the tooth to the tooth holder, and saidsecond resilient member adapted to be compressed between said secondprong and said second side wall of said web to frictionally secure thetooth to the tooth holder.
 10. The tooth assembly according to claim 9wherein said first and second spaced apart prongs define an elongatedslot having a closed inner end and an open outer end, said first andsecond resilient members each having an outer end adjacent said outerend of said slot and an inner end adjacent said inner end of said slot.11. The tooth assembly according to claim 10 wherein said nose end ofsaid web is adapted to engage said inner end of said slot.
 12. The toothassembly of claim 10 wherein the first and second resilient members areadapted to engage said first and second opposite side walls alongsubstantially the entire length thereof between said nose end and saidinner end of said web.
 13. The tooth assembly according to claim 9wherein each of said first and second resilient members are attached tothe assembly by a vulcanization process.
 14. The tooth assemblyaccording to claim 9 wherein each of said first and second side walls ofsaid web are concave in cross section.
 15. A method for detachablysecuring a tooth to a tooth holder comprising: providing said toothholder with upper and lower members and a web extending between saidupper and lower members, said web being elongated, having a nose end, aninner end, and an elongated first and second opposite side wallsextending along the length thereof between said nose end and said innerend; providing said tooth with a cutting end and an attachment end, saidattachment end having a first and second spaced apart prongs forming anelongated slot, said slot having a closed inner end and an open outerend; attaching first and second resilient members either to said firstand second prongs respectively or to said first and second side wallsrespectively of said web; moving said first and second prongs of saidtooth holder into an attached position engaging said first and secondopposite side walls respectively of said web, so that said firstresilient member is compressed between said first prong and said firstside wall of said web and said second resilient member is compressedbetween said second prong and said second side wall of said web.
 16. Themethod according to claim 15 wherein said attaching step comprisesvulcanizing said first and second resilient members either to said firstand second prongs respectively or to said first end second side wallsrespectively of said web.
 17. The method according to claim 15 whereinsaid first and second resilient members are elongated and include aninner end adjacent said inner end of said slot and an outer end adjacentsaid outer end of said slot, said step of moving said tooth holder tosaid attached position includes moving said closed inner end of saidslot into contact with said nose end of said web whereby said first andsecond resilient members engage said first and second side wallsrespectively along substantially their entire lengths between said innerend and said nose end of said web.